Background: Vulnerability to the reduction in natural light associated with fall/winter is generally accepted as the main trigger of seasonal affective disorder (SAD), whereas light therapy is a treatment of choice of the disorder. However, the relationship between exposure to light and mood regulation remains unclear. As compared with green light, blue light was shown to acutely modulate emotion brain processing in healthy individuals. Here, we investigated the impact of light on emotion brain processing in patients with SAD and healthy control subjects and its relationship with retinal light sensitivity.

In a prospective study, we examined the efficacy of risperidone added-on to mood stabilizers in the acute and continuation treatment of mania over a 12-week period. Patients (n=108) with a DSM-IV diagnosis of bipolar disorder, manic or mixed episode requiring treatment with an antipsychotic were recruited. All subjects were on one or two mood stabilizers at the time of initiation of risperidone (range 0.5-4 mg). No other antipsychotic medication or ongoing benzodiazepine therapy was allowed. There was a significant decrease in mean Young Mania Rating Scale (YMRS) scores from baseline (27.5+/-7.5) to week 1 (-10.8, P<0.0001), week 3 (-17.7, P<0.0001) and to week 12(-22.6, P<0.0001). When response was defined as > or = 50% reduction in YMRS scores from baseline, 32%, 68% and 90% of patients met criteria at week 1, week 3 and week 12, respectively. Significant decreases in mean 21-item Hamilton Depression Rating Scale scores from baseline (12.2+/-7.7) to week 3 (-5.7, P<0.0001) and week 12 (-5.7, P<0.0001) were also observed. No significant changes in extrapyramidal symptoms were noted between baseline and endpoint. The mean daily dose of risperidone was 2 mg with a median of 1.8 mg. These findings support the results of the two previous double-blind, randomized trials and indicate that the addition of risperidone to mood stabilizers is a safe and effective treatment for acute and continuation treatment of mania. Risperidone add-on does not induce depressive symptoms and, furthermore, risperidone may have efficacy in treating comorbid depressive symptoms in bipolar patients.